A mutation affecting eye color was discovered in Macrolophus pygmaeus (Rambur) (Hemiptera: Miridae). This species is an important biological control agent used to manage whiteflies and other arthropod pests in greenhouse crops. Typically, these predators exhibit a dark eye coloration, ranging from garnet to black. However, individuals with bright red eyes have been identified within wild populations, making them easily distinguishable. The objective of this study was to study the mode of inheritance of the red eye color mutation observed. Additionally, a comparative analysis of key biological traits was conducted between individuals carrying the mutation and those from a wild-type population. From these specimens, a population carrying this eye color mutation, referred to as ruby, was established. Genetic analyses revealed that the red coloration is controlled by a single recessive allele located on an autosomal chromosome. Red-eyed individuals exhibited superior performance in biological traits, including greater body size in both males and females, as well as increased fecundity and longevity in females. The utilization of this red-eyed variant could be valuable as a visual marker in ecological and biological studies of population dynamics.